A broad staircase leads from the South Propylea and on to the Piano Nobile, believed to house the official apartments based on finds that had fallen onto the floor below. The upper floor was dissected by a long open corridor off which is a porticoed lobby, which opens on to a hall with three columns. Off this room is a small room referred to as the Treasury because of the valuables found beneath it.

From the three-columned room a staircase leads down from the upper hall to the Central Court (see below). Continuing along the upper corridor there were two rooms, a Great Hall with two central columns and a smaller room with six columns.